In the practice of medical diagnostics, it is often necessary to perform a biopsy to remove a sample of a patient's tissue or fluid for pathological study. For example, biopsies can be useful in diagnosing various forms of cancer and other diseases affecting a localized area of tissue. Biopsy procedures may be used to take tissue and/or fluid samples from muscles, bones and organs, such as the liver or lungs. In some instances, a biopsy sample may be obtained by invasive surgical procedures. However, minimally invasive biopsy procedures are often preferred, such as fine needle aspiration and fine needle biopsy because such procedures are less traumatic to the patient.
Both fine needle aspiration (FNA) and fine needle biopsy (FNB) procedures generally include the use of a biopsy needle for collecting the target sample. FIGS. 1 and 2 are provided to illustrate one embodiment of a biopsy needle 100 currently available for use in biopsy procedures. As shown, the needle 100 includes a shaft 102 portion extending from a proximal end (not shown) to a distal cutting end 104 of the needle 100. The distal cutting end 104 includes a beveled leading end 106 resulting in a relatively sharp tip portion 110 used for puncturing the tissue to be sampled. The distal cutting end 104 of the needle 100 may be configured to cut and/or scrape target tissue to collect cells, tissue, or fragments. To sample the target area, the biopsy needle 100 may be guided to the tissue to be sampled through an instrument positioned in a patient. The instrument may be used with an endoscope, conduit and/or medical device insertion instrument. As shown, the needle 100 may be positioned within a sheath 108 of an endoscopic device, for example, such that the biopsy needle 100 may be retracted and extended from the sheath 108.
Upon contacting the tissue to be sampled (via the distal cutting end 104), the tissue sample may be collected within a lumen 112 of the shaft 102. In some devices, the needle 100 may extend from the sheath 108 and into the target tissue via a spring mechanism (not shown), such that the spring applies a force to the needle 100 and subsequently forces the distal cutting end 104 into the target tissue. Upon making contact with the target tissue, the distal cutting end 104 may separate a portion of the tissue from the surrounding tissue and collect the separated tissue within the lumen 112, which may result in a “core” sample (e.g., a number of intact adjacent cells held together in similar form to their native location). Additionally, or alternatively, suction may be applied to the proximal end of the needle 100 so as to aspirate the sample (e.g., cells, tissue, etc.) through the distal cutting end 104 of the needle 100 and into the lumen 112.
Generally, the goal of FNA and/or FNB is to acquire sufficient tissue to allow a diagnosis to be made. Currently, different needle tip configurations are used to collect different sample types (e.g., intact multi-cell samples useful for histology, cells and fragments useful for cytology, etc.). However, many existing biopsy needles are inefficient when collecting samples. For example, some needles use only about half or less of their inner diameter of the lumen to obtain tissue. Further, some current needle tip designs generally result in tearing of target tissue, which may result in a less than ideal core sample and unnecessary trauma to the surrounding tissue, which may cause further complications to the patient (e.g., internal bleeding, bruising, etc.) requiring further treatment.
Some devices that obtain a full cylinder or “full core” of tissue have difficulty in withdrawing tissue and/or in maintaining the physical state of the tissue so as to provide an accurate assessment of tissue condition. For example, some needles rely on scoring and/or mashing techniques during tissue collection, which may result in a damaged tissue sample. Depending on the diagnostics, physical characteristics of tissue, such as placement or orientation of cells or tissue, may be as important or more important than the chemical or biological characteristics (e.g. presence of malignant cells or by-products).
Furthermore, current needle tip designs may be insufficient for biopsy of certain types of tissue. For example, some lesions are particularly fibrous (e.g., pancreatic lesions) and are difficult to penetrate and obtain a suitable biopsy therefrom. Some bevel designs, such as the standard beveled cutting end of needle 100, may initially pierce a portion of the target lesion, but may then deflect off of or drift from the target lesion due to the inadequate tip design and/or inability to fully penetrate the lesion, which results in a poor tissue sample, and may even lead to damage to surrounding tissues or vital organs. Additionally, current bevel designs may merely shear off a portion of the target tissue and fail to collect some, or even all, of the sampled tissue within the lumen of the needle due to inadequate tip design.